Metal-containing detergent-dispersants for lubricants



United States Patent 3,451,931 METAL-CONTAINING DETERGENT-DISPERSANTSFOR LUBRICANTS Donald J. Kahn, Metuchen, Frieder S. Fur-er, Wayne,

and Max L. Robbins, South Orange, N.J., assignors to Esso Research andEngineering Company, a corporation of Delaware No Drawing.Continuation-impart of application Ser. No. 333,614, Dec. 26, 1963. Thisapplication Aug. 30, 1966, Ser. No. 575,971

Int. Cl. (310m 1/32, 3/20, 5/20 US. Cl. 252--32.7 20 Claims ABSTRACT OFTHE DISCLOSURE This application is a continuation-in-part of applicationSer. No. 333,614, filed Dec. 26, 196 3, and now abandoned.

The present invention relates to improved detergentdispersant typeadditives for lubricating oil compositions, to processes for making suchadditives, and to finished lubricating oil compositions and oilconcentrates containing such additives. The additives may becharacterized generally as colloidal dispersions of metal salts, e.g.,alkali "metal and/or alkaline earth metal salts, principally salts ofacidic gases, e.g., carbonates of those metals, in admixture Withcertain nitrogen containing derivatives of high molecular Weightcarboxylic acids, e.g., alkenyl succinic acid anhydrides, these lattermaterials serving both as dispersing aids for the colloidal dispersionand as detergents and/or dispersants in the lubricating oil compositionin which the additives are incorporated.

In order to ensure adequate lubrication of high compression piston-typeinternal combustion engines, i.e., to minimize wear and to keep thevarious parts of the engine free of varnish, carbonaceous deposits andsludge, it has been found necessary to employ in the lubricants for suchengines various types of detergent additives. Studies over a number ofyears have lead to the development of the so-called basic soaps oroverbased salts of various organic acidic materials such as metal alkylphenates, metal salts of alkyl phenol sulfides (i.e., thioethers ofalkyl phenols), metal salts of organic sulfonic acids, and the like. Onemethod for the preparation of such basic soaps or salts involves themere use of an excess of neutralizing agent in the form of an oxide,hydroxide or carbonate of the desired metal. This produces a materialwhich contains an amount of metal in excess of the amount that istheoretically required to replace the acidic hydrogen of the organicacid that has been employed as the starting material. Related additivesthat have the advantage of basicsalts are metal complexes or colloidaldispersions of inorganic salts or of metal oxides or hydroxides whereinthere is a high ratio of metal to organic acid component. It is to thislatter type of additive that the present invention is directed.

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Earlier workers in the art of lubricant additives have proposed thepreparation of a detergent-dispersant or combined detergent andinhibitor additive by reacting a metal base, usually an alkaline earthmetal oxide and/ or hydroxide with an acidic gas, usually carbondioxide, in the presence of one or more of various promoters such asalkyl phenols and in the presence of a dispersant such as aphosphosulfurized hydrocarbon. In systems of this nature, thephosphosulfurized hydrocarbon serves as a dispersant that maintains thecolloidal dispersion. In previous work it was found that in order toincrease the metal content of the system it was necessary to increasethe'amount of dispersant also. Inasmuch as the dispersant represents aconsiderable item in the overall cost of the additive composition, therehas been an incentive to develop methods for attaining high ratios ofmetal to dispersant in stable compositions of this type. Some priorpatents relating to system of this type include U.S. Patents Nos.2,616,911, 2,695,910, 2,723,235, 2,777,874, 2,- 856,360, 2,956,018, and3,057,896.

It has now been found, in accordance with the present invention, that ametal-containing detergent-dispersant additive (particularly onecontaining an alkali metal or alkaline earth metal) having a high ratioof metal to dispersant can be prepared by suspending a metal base, e.g.,an alkali metal or alkaline earth metal oxide or hydroxide, in anitrogen-containing dispersant derived from a high molecular weightcarboxylic acid such as alkenyl succinic anhydride and treating thesuspension with an acidic gas such as carbon dioxide. The resultingmaterial is a colloidal dispersion of metal salt, e.g., carbonate, inwhich the colloidally dispersed salt contributes detergency and thuscooperates with the dispersant to furnish a highly effectivedetergent-dispersant additive for oil compositions.

The nitrogen-containing dispersants that are employed in the presentinvention are derivatives of high molecular weight carboxylic acids. Onecommonly used type comprises alkenyl succinic anhydride derivatives,including those selected from the class consisting of the reactionproducts of alkenyl succinic anhydrides with polyamines (see U.S.Patents Nos. 3,172,892, 3,154,560, 3,024,237, etc), other amines (seeUS. Patent No. 3,219,666), the reaction products of alkenyl succinicanhydrides with polyamines and carboxylic acids (see US. Patent No.3,216,936), the products obtained by further reacting the lattermaterials with acidic organic compounds containing phosphorus and sulfur(see US. Patents Nos. 3,184,412 and 3,185,643), and the reactionproducts of alkenyl succinic anhydrides with polyhydric alcohols andpolyamines.

Other nitrogen-containing dispersants are taught in Belgian Patent No.662,875 wherein a nitrogen-containing hydroxy compound is reacted withan alkenyl succinic anhydride to form an ester. Specifically, thisBelgian patent teaches dispersants comprising N alkyl morpholinoneesters, e.g., the ester of N (2 hydroxyethyl) 2 morpholinone and apolyisobutenyl succinic anhydride.

Thus, the dispersants employed in the present invention comprise amides,imides, salts and esters prepared by reacting monocarboxylic orpolycarboxylic acids of high molecular Weight with organic compoundscontaining amino nitrogen and/or heterocyclic nitrogen and having atleast one amino group or hydroxyl group capable of forming the saidamide, imide, salt or ester. The high molecular weight acid is onehaving in the range of about 40 to 250 carbon atoms and includesunsubstituted and substituted monocarboxylic and polycarboxylic acids.

Monocarboxylic acids for use in the present invention will havemolecular weights in the range of about 600 to 4000, preferably fromabout 700 to 3000. Such acids can be prepared by oxidizing highmolecular weight olefins, e.g., polyisobutylene of about 900 molecularweight, with an oxidizing agent such as nitric acid or oxygen, byaddition of an aldehyde to an olefin followed by oxidization of theadducts, or by addition of halogen to a high molecular weight olefin toform a dihalogen compound followed by hydrolyzing oxidation of thelatter. These procedures are taught in British Patent No. 983,040.

A suitable monocarboxylic acid or derivative thereof can also beobtained by oxidizing a monohydric alco hol with potassium permanganateor by reacting a halogenated high molecular olefin polymer with aketene. Another convenient method for preparing a monocarboxylic acidinvolves the reaction of metallic sodium with an acetoacetic ester of amalonic ester of an alkanol to form a sodium derivative of the ester andthe subsequent reaction of the sodium derivative with a halogenated highmolecular weight hydrocarbon such as brominated wax or brominatedpolyisobutylene.

Monocarboxylic acids may also be prepared from olefin polymers such as apolymer of a C to C monoolefin, e.g., polypropylene or polyisobutyleneby halogenationg the polyolefin and then condensing it with anunsaturated monocarboxylic acid. Examples of suitable olefin polymersinclude polyethylene, polypropylene, or polyisobutylene, having anaverage molecular weight of about 600 to 3000, preferably about 800 to1900. Such polymers have from about 40 to 250 carbon atoms, or morepreferably, about 50 to 120 carbon atoms per molecule. Polyisobutyleneis preferred since it has a lessened tendency to gel the product, ascompared to some of the other polyolefins such as polyethylene orpolypropylene. The polymer is halogenated by contacting it with eitherbromine or chlorine, preferably by blow ing chlorine through thepolymer, to provide about one to two atoms of halogen per molecule ofpolymer. The halogenation step may be conducted in the temperature rangeof from about 50 to about 300 F. To aid in the halogenation step, thepolymer may be dissolved in a suitable solvent, such as carbontetrachloride, in order to lower the viscosity of the polymer. However,the use of such a solvent is not necessary.

The time required for halogenation may be varied to some extent by therate at which the halogen is introduced. Ordinarily from about 2 toabout 5 hours is a satisfactory halogenation period. In a representativeplant scale operation involving the chlorination of polyisobutylene of830 molecular weight, a 100-pound batch will be chlorinated with poundsof chlorine introduced into the reactor over a period of 3 /2 hours witha chlorination temperature of about 250 F.

The halogenated polymer thus obtained is condensed with an alpha,beta-unsaturated, monocarboxylic acid of from 3 to 8 carbon atoms.Ordinarily, because of their greater avaliability, acids of this classhaving 3 or 4 carbon atoms will be used. Such acids include acrylicacid, alpha-methyl-acrylic acid (i.e., 2 methyl propenoic acid) crotonicor isocrotonic acid, tiglic acid, angelic acid, sorbic acid and cinnamicacid.

In condensing the halogenated polyolefin with the unsaturated acid, atleast one mole of acid is used per mole of halogenated polyolefin.Normally, the acid will be employed in excess and may amount to as muchas 1.5 to 2 moles per mole of halogenated polyolefin. The condensationtemperature may be in the range of from about 300 to 500 F. and willmore preferably be with in the range of from about 375 to 475 F. Thecondensation may require from about 3 to about 24 hours, but willordinarily take place in from 6 to 18 hours. After the reaction has beencompleted, excess acid may be purged from the mixture, for example, byblowing 2 3th a stream of nitrogen at a temperature of 400 {0 Highmolecular weight carboxylic olefin acids of this type can also beprepared by a so-called one-step process involving the halogenation ofthe olefin polymer in the presence of the alpha, beta-unsaturated acid.Using proportions of reactants within the ranges discussed above, thestarting acid and the olefin polymer are mixed together in the reactor,the temperature being kept below about F. until the start of halogenintroduction so as to avoid homopolymerization of the alpha,beta-unsaturated acid. Once halogenation has begun, the temperature maybe raised to as high as 250 F. After halogen introduction thetemperature may be raised to 300 to 500 F. to effect the condensationreaction.

A polycarboxylic acid for use in the invention may be prepared byhalogenating a high molecular weight hydrocarbon such as the olefinpolymer described hereinabove to produce a poly-halogenated product,converting the poly-halogenated product to a poly-nitrile, and thenhydrolyzing the poly-nitrile. Polycarboxylic acids may be prepared alsoby oxidation of a high molecular weight polyhydric alcohol withpotassium permanganate, nitric acid, or a like oxidizing agent. Anothermethod for preparing such polycarboxylic acids involves the reaction ofan olefin or a polar-substituted hydrocarbon such as achloro-polyisobutylene with an unsaturated poly-carboxylic acid such as2 pentene- 1,3,5 tricarboxylic acid obtained by dehydration of citricacid.

A particularly useful polycarboxylic acid is analiphatichydrocarbon-substituted succinic acid or anhydride. Thepreparation of an alkenyl succinic anhydride is wellknown in the art andsimply involves reacting maleic anhydride with an organic compoundhaving an olefinic linkage. Generally, about equal molar proportions ofmaleic anhydride and the olefinic material are simply heated together.In some cases somewhat of an excess of olefinic material may be used;also in some instances catalysts may be employed in the reaction. Theparticular mode of preparing the alkenyl succinic anhydride is not theconcern of the present invention.

The alkenyl succinic anhydrides may be represented by the followingformula:

In the above formula R and R can be either hydrogen or hydrocarbonradicals but at least one of them must be a hydrocarbon group. Thehydrocarbon radicals may be either substituted, as for examplechlorinated or sulfurized, or they may be unsubstituted and they willinclude aliphatic, acyclic and aromatic radicals. Preferably, the totalnumber of carbon atoms in R and R combined is within the range of fromabout 40 to 250, more preferably within the range of from about 50 toabout 120. Particularly desirable for use in this invention because oflow cost and ready availability are alkenyl groups obtained bypolymerizing a C to C monoolefin to a polymer having a molecular weightwithin the range of from about 500 to about 3500. More specifically, thealkenyl group may be derived from polypropplcne or polyisobutylene ofabout 700 to 1700 molecular weight.

Substituted acids can also be used in making the dispersant. Forexample, keto acids can be prepared by con densing alkylated arylcompounds with dibasic acids, e.g., maleic acid or succinic acid,dibasic acid anhydrides, e.g., phthalic anhydride, or dibasic arylhalides, e.g., adipic acid chloride, in the presence of a Friedel-Craftscatalyst, such dibasic acid compounds having a total carbon content inthe range of from 4 to 20 carbon atoms. The alkylated aryl compoundsinclude alkylated aromatic hydrocarbons such as alkylated benzenes,naphthalenes and anthracenes and alkylated phenols having from 1 to 6carbon atoms in the alkyl chain. These keto acids are characterized bythe following general formula:

o RAr( iR( iJOH In the above formula R is a hydrocarbon radical havingin the range of from 2 to about 18 carbon atoms, preferably from about 2to 6 carbon atoms, and the symbol Ar is an aromatic radical having inthe range of 6 to 16 carbon atoms. The symbol R in the above formula isat least one aliphatic hydrocarbon radical having in the range of from12 to 30 carbon atoms, which can be derived by alkylating the aromaticcompound, e.g., benzene, phenol, naphthalene, etc., with halogenatedparaffin wax, chlorinated gas oil, brominated cetane, etc.

When the dispersant used in this invention is an amide, imide or salt ofan amine and a carboxylic acid it is preferred that the amine be apolyamine such as diethylene triamine, tetraethylene pentamine,octaethylene nonamine, tetrapropylene pentamine, andN,N-di-(2-aminoethyl) ethylene diamine. The polyamine may be representedby the general formula wherein n is 2 to 3 and m is a number from 0 to10.

The use of N-aminoalkyl piperazines, mixtures of different alkylenepolyamines, mixtures of different N- aminoalkyl piperazines, andmixtures of N-aminoalkyl piperazines with alkylene polyamines is alsowithin the scope of this invention.

Ester-type dispersants used in this invention include not only theN-alkyl morpholinone esters previously mentioned but also esters ofother hydroxy alkyl nitrogencontaining compounds, e.g.,N-(Z-hydroxyethyl) ethylene diamine, l,4-bis(2-hydroxypropyl)piperazine, N,N'-bis (2-hydroxyethyl) ethylene diamine, anddihydroxypropylsubstituted tetraethylene pentamine. Particularly usefulare the polyhydroxy alkyl tertiary amines, e.g., N,N,N',N tetrakis(hydroxyalkyl) alkylene diamines, which may also be referred to asalkylene dinitrilotetraalkanols. These may be represented by thefollowing general formula:

where R is a member selected from the group consisting of hydrogen atomsand alkyl groups containing 1 to 2 carbon atoms, and R is an alkyleneradical of from 2 to 6 carbon atoms. Some of the hydroxyalkyl alkylenediamines are available commercially. Specific examples of thesecompounds include ethylene dinitrilotetraethanol, propylenedinitrilotetrabutanol and ethylene dinitrilotetrapropanol.

The above hydroxyalkyl alkylene diamines may be prepared by reacting analkylene oxide containing 2 to 4 carbon atoms with an alkylene diaminesuch as ethylene diamine, propylene diamine, or hexamethylene diamine.In this reaction, about 4 moles of the alkylene oxide will be reactedwith each mole of alklene diamine. If the molar proportions are changed,other polyhydroxy alkyl amines useful in this invention are obtained,such as the following:

HOCHzGHz CH2CH2OH NCH2CH2-NCH2CH2N HOCHzCHz CHzCHzOH OI-IzCHzOH Any ofthe aforesaid monocarboxylic or polycarboxylic acids can be reacted withany of the aforesaid amines, polyamines or nitrogen-containing hydroxycompounds. Thus, one type of dispersant is prepared by reaction of analkenyl succinic anhydride with a polyamine under conditions evolvingwater of reaction; using from 0.5 to 4.0 moles of the anhydride per moleof polyamine. Generally, in preparing any of the reaction products ofthe polyamines with monocarboxylic acids or polycarboxylic acids it isdesirable to use suflicient of the acid to react with at least one aminogroup per molecule of polyamine, and the amount of acid used may evenexceed the amount that is sufficient to react with every amino group inthe polyamine molecule. There is usually no advantage in using less thanone-half equivalent of the polyamine per equivalent of carboxylic acid.With respect to this notation, the number of equivalents in thepolyamine depends upon the number of amino groups present; thus,tetraethylene pentamine has 5 equivalents. Similarly, an alkenylsuccinic acid or anhydride has two equivalents, and a monocarboxylicacid has one equivalent.

As stated above, in addition to the dispersants prepared by reactingalkenyl succinic anhydrides with polyamines, another type of dispersantthat can be employed in the present invention is prepared by reaction ofan alkenyl succinic anhydride with a polyamine and a carboxylic acid.One method of preparing such an additive involves a two-stage processwherein the first stage is the reaction of a carboxylic acid with apolyamine to form an imidazoline which is then condensed with thealkenyl succinic anhydride in a second stage. The carboxylic acidemployed is one having from 1 to 30 carbon atoms in an aliphatichydrocarbon chain and is preferably a carboxylic acid having from 1 to18 carbon atoms. The aliphatic chain may be either branched or straightchain and either saturated or unsaturated. The acids may be eithermonocarboxylic or dicarboxylic and include acetic, fumaric, adipic,lauric, oleic, linoleic, and stearic acids. Additives of this type canalso be prepared more simply by simultaneously reacting the carboxylicacid, the polyamine, and the alkenyl succinic anhydride.

An additional type of dispersant that is useful in the present inventionis obtained by further reacting the reaction product of an alkenylsuccinic anhydride, a carboxylic acid, and a polyamine with an acidicorganic compound containing phosphorus and sulfur. More specifically, anacidic organic compound is employed from the class consisting ofphosphosulfurizedl hydrocarbons and dialkyl dithiophosphoric acids.

Imidazolines can be prepared by simple mixing of substantiallystoichiometric proportions of a polyamine and a carboxylic acid followedby heating to reflux and removal of the water of condensation. To aid inremoving the water of reaction an inert solvent such as heptane ortoluene can be used as a water entraining agent. The solvent can then beremoved later by evaporation. The imidazoline thus formed can then bereacted with the alkenyl succinic anhydride. The reaction is preferablycarried out with equal molar proportions of the two reactants, thereaction being conducted by heating to reflux temperature and removingthe water of condensation. As in the first stage, an inert solvent canbe used to aid in removing water.

In an improved method of preparing reaction products of alkenyl succinicanhydrides, carboxylic acids and polyamines equimolar proportions of thealkenyl succinic anhydride, the polyamine and the carboxylic acid may bereacted together. However, variation in these relative proportions canbe made, for example, 0.5 to 4.0, preferably 0.5 to 1.5 moles of theanhydride and] 0.5 to 4.0, preferably 0.5 to 1.5 moles of the carboxylicacid can be used per mole of polyamine.

While generally in any of the reactions involving an alkenyl succinicanhydride and a polyamine or any of the modifications discussed above,the reactants upon simple mixing will interact to some extent, theproducts will generally be oil-insolube. However, upon heating (e.g., toabout 200 to 250 F.) the reaction mixture will becomemineral-oil-soluble, and upon continued heating condensation reactionswill begin to take place with the evolution of water. The evolved watercan be readily removed by blowing nitrogen or other nonreactive gasthrough the reaction mixture during the course of the reaction. Thereaction may be carried out by heating the three reactants for about 1to 30 hours at 250 to 350 F. Preferred reaction conditions includeheating for 6 to 20 hours at 275 to 300 F. Preformed alkenyl succinicanhydride can be used, or the alkenyl succinic anhydride can be made byfirst reacting the olefinic material with the maleic anhydride to formthe alkenyl succinic anhydride, thereafter adding the polyamine (and thecarboxylic acid when it is used in the reaction) to the hot alkenylsuccinic anhydride, and then preferably further heating to form acondensation product. Preferably, a light mineral oil is added to thereaction mixture as a diluent after the formation of the alkenylsuccinic anhydride and before the addition of the polyamine or thepolyamine plus fatty acid. An antifoamant agent such as a polysiliconecan be added to the reaction mixture in order to prevent foaming duringthe addition of the amine.

Also contemplated for use in this invention are dispersants prepared byreacting an alkenyl succinic acid or anhydride with a polyhydric alcoholor an alkanolamine and subsequently with a polyamine in accordance withthe procedure taught in U.S. Patent No. 3,184,474. In preparing thesedispersant additives, the polyamines and the alkenyl succinic anhydridesare of the same nature as disclosed above. The Polyhydric alcoholsinclude alkylene glycols, such as ethylene glycol, propylene glycol,butanediol-1,4- pentanediol-l,5, octylene glycol, and polyalkyleneglycols, such as polyethylene glycols and polypropylene glycols. Thealkanolamines include triethanolamine and diethanolamine. In general,the polyhyldric alcohols and alkanolamines contain in the range of from2 to 36, and preferably from 4 to 18, carbon atoms. While equimolarproportions of each of the three reactants are normally used, from 0.75to 2.0 molar proportions of the polyhydric alcohol or alkanolamine andfrom 0.75 to 2.1 molar proportions of the polyamine can be used for eachmolar proportion of the alkenyl succinic anhydride. In preparing theadditive the polyhydric alcohol or alkanolamine and the alkenyl succinicanhydride are refluxed together for from 1 to 24 hours, after which thepolyamine is added and refluxing is continued for 1 to 24 hours, whileremoving water of condensation.

When preparing a dispersant by condensing a keto acid with apolyalkylene polyamine conditions are used to favor the formation ofamides with the carboxyl groups of the keto acids, although some of theproduct may con tain Schiff base derivatives resulting from reactionwith the keto groups. One or more of the amino groups of the polyaminemay enter into either the amide-forming reaction or the Schiff baseforming reaction. Generally, the mole ratio of polyamine to keto acidwill range from about 1:5 to about 3:1 although it is preferred thatthis ratio be in the range of from about /2 mole of polyamine percarboxylic acid group up to about 2 moles of polyamine per carboxylicacid group. The reaction temperatures for amide formation will generallybe in the range from about 200 to 400 F.; in most cases, however, anarrower range of from about 250 to about 350 F. will be used. Thereaction time will depend to some extent upon the reaction temperature.The composition of the reaction can be determined by measuring theamount of water that is split off during the reaction. If desired, awater entraining solvent such as heptane or toluene can be employed toremove the water as an azeotrope.

Similar reaction conditions are used in preparing amides of the othermonocarboxylic acids disclosed above. For example, polyisobutenylpropionic acid may be reacted with triethylene tetramine by heating for6 to 20 hours at 275 to 320 F.

The metal component of the metal salts of this invention may be one of anumber of light or heavy metals, mono or polyvalent. While the alkalimetal or alkaline o earth metals are particularly advantageous othermetals can be used as Well. The former include sodium, potassium,lithium, calcium, barium, strontium and magnesium. Other specific metalsinclude zinc, cadmium, mercury, lead, tin, iron, cobalt, copper,manganese, aluminum, chromium, nickel, antimony, etc.

These meals are usually employed in the invention in the form of basiccompounds, including oxides, hydroxides and hydrated oxides or hydratedhydroxides.

The acidic gases usable in the invention include HCl, S0 S0 CO air(considered acidic because of CO content), N0 BF H S, etc. Mostgenerally H 8, S0 or CO will be used. In most instances carbonate saltsare advantageously employed in the dispersions of the invention.

While the colloidal dispersions could be prepared in the dispersantmaterial per se, it is usually more convenient to prepare them in amixture of dispersant and oil, thus providing an additive concentratefor further use.

In preparing colloidal metal salt dispersions in an oleaginous mediumthere are at least three factors that must be considered. One of theseis to obtain good contact between the metal base and the acidic gas,e.g., carbon dioxide. This requires that at least some polar material,usually water, be present to solubilize, totally or in part, the metalbase, e.g., oxide or hydroxide. Another factor is to condition the polarphase so as to facilitate transfer of the formed metal carbonate intothe oil phase. A third factor is to stabilize the metal salt dispersionor sol. The latter is accomplished by the dispersant additives discussedabove.

To facilitate transfer of the metal salt across the interface betweenthe polar phase and the oil phase, auxiliary dispersants, surface activematerials or promoters may be employed. Promoters include such materialsas alcohols, alkylphenols, for example, amylphenol, octylpheno, ornonylphenol, carboxylic acids such as benzoic acid, oleic acid, tall oilfatty acids, or the like, various amino compounds such asisopropanolamine, ethylene diamine, diethylene-triamine, or the like.Other promoters are listed in Us. Patent Nos. 2,856,360; 2,695,910;2,777,874; etc.

While the exact function of the promoter is not known. all of thepromoters that have been found to be effective are characterized byhaving a hydrophilic portion, e.g., an OH or a NH group and anoleophilic portion which is usually a hydrocarbon group. One theory isthat the promoter bridges the polar phase where the reaction occurs andthe hydrocarbon phase in which the resulting salt is subsequentlydispersed.

To ensure the fineness of particle size that is necessary to obtain thecolloidal dispersion, high speed mixing may be employed, or a techniquemay be used which involves the preparation of a microemnlsion, addingthe metal base, usually an alkali metal or alkaline earth hydroxide tothe microemnlsion, treating the mixture with the acidic gas, such ascarbon dioxide, and then stripping off the water. The microemulsiontechnique involves the formation of an emulsion wherein the droplets inthe disperse phase are at least smaller than 400 A. so that the emulsionis clear or at the most only very slightly hazy. To form amicroemnlsion, water or a C to C aliphatic alcohol is dispersed in aliquid hydrocrabon containing a balanced mixture of dispersantscomprising carboxylic acids and alkanolamines.

A microemnlsion may be prepared at ambient temperatures. The addition ofthe metal base is preferably conducted after the microemulsion has beenheated at an elevated temperature to 250 F.; more usually to 200 F.) andthe treatment with CO or other acidic gas is also preferably conductedat an elevated temperature (125 to 300 F.; more usually to 250 F.).Water can be removed from the product by sparging with an inert gas suchas nitrogen at temperatures in the range of 200 to 400 F., moregenerally 275 to 325 F. The rate of CO flow at the start of the COtreatment should preferably not exceed that rate at which the CO contentof the exit gas indicates a 25 to 50% loss of unreacted CO That flowrate is then held constant until the exit gas indicates that loss ofunreacted C exceeds about 90%. Normal reaction times are about 1.5 to2.5 hours. In preparing additives of the present invention by the highspeed stirring technique, a solution or blend of the dispersant, e.g.,alkenyl succinic anhydride derivative, and any promoter or auxiliaryagents that are to be used, is prepared in a hydrocarbon oil, using heatand stirring if necessary to efiect the solution or blending. Thehydrocarbon oil may comprise any fraction that has a sufficiently highboiling point so that it will not vaporize under the reactionconditions. Light lubricating oil fractions are particularly suitable.The solution or blend is then subjected to high speed stirring while thedesired base, usually metal oxide or hydroxide is added gradually andsimultaneously with the introduction of a stream of acidic gas such ascarbon dioxide. If water is needed in the reaction it is either addedinitially or it may be added dropwise along with the metal base, e.g.,oxide or hydroxide. At the end of the reaction period the product isdehydrated and filtered. The broad and preferred temperature ranges forthe steps are given in Table I.

The time required for addition of the metal base may range from about 30minutes to about 6 hours, and will more generally range from about 1 to3 hours. The dehydrating step may require from 15 minutes to about 45minutes.

The proportions of reacting materials may vary within the ranges shownin Table II.

TABLE II Weight percent Broad Preferred Alkenyl succinic acid derivativeor other dispersant 5-35 15-25 Alkylated phenol and auxiliary agents1-15 2-7 Water 1 0-10 0. 1-1. 5

Metal oxide (or equivalent metal base,

hydroxide) l -50 20-40 Diluent oil 20-80 40-60 v 1 Ordinarily not neededif metal base is hydrated hydroxide such as B8.(0H)z.5Hz0.

The dispersions prepared in accordance with this invention are additiveconcentrates containing in the range of 5 to 50% dispersant materialsand from 10 to 35% metal salt, e.g., sulfide, nitrite, carbonate, etc.Normally, although not necesarily, mineral oil diluent will be presentas a third component of the dispersion. These concentrates may be addedto any of several types of oil compositions ranging from fuel oilsthrough lubricating oils. The lubricating oils to which they may beadded include mineral lubricating oils and synthetic oils. The minerallubricating oils include those derived from parafiinic, naphthenic,asphaltic, or mixed base crude oils. Synthetic hydrocarbon lubricatingoils may also be employed. Other synthetic oils include dibasic acidesters such as di-Z-ethyl hexyl sebacate, carbonate esters,polysilicones, halogenated hydrocarbons, phosphate esters, polyglycols,glycol esters such as C oxo acid diesters of tetraethylene glycol, andcomplex esters, e.g., one formed by reaction of 1 mole of sebacic acidwith 2 moles of tetraethylene glycol and 2 moles of 2-ethyl hexanoicacid.

For lubricating oil compositions the concentrates may be added inamounts ranging from about 0.1 to about 10 weight percent, to furnishfrom about 0.01 to about 10 3 weight percent of metal, depending uponthe particular use. For example, in crankcase lubricants concentrationsproviding from about 0.02 to about 0.6 weight percent of metal areadvantageous, while for marine diesel lubrication concentrationsproviding as much as 1.5 to 2 weight percent of a metal such as calciummight be used.

The additives of this invention may also be employed in middledistillate fuels for inhibiting corrosion and the formation of sludgeand sediment in such fuels. Concenration ranges of from about 0.002 toabout 2 weight percent, or more generally from about 0.005 to about 0.2weight percent, are employed. These additives may also be used inconjunction with ashless additives for fuels, such as polymers ofacrylic or methacrylic acid esters, high molecular weight aliphaticamines, etc. Petroleum distillate fuels boiling in the range of fromabout 300 to about 900 F. are contemplated. Typical of such fuels areNo. 1 and No. 2 fuel oils that meet ASTM Specification D-396-48T, dieselfuels qualifying as Grades 1D, 2D, and 4D of ASTM SpecificationD-975-51T, and various jet engine fuels.

The additives may also be used in residual fuels. Magnesium compoundsare of particular value for addition to residual fuel oils containingvanadium compounds. The latter are objectionable because the ash ends tobe corrosive to metal parts exposed to high temperatures. Magnesiumcompounds combat this oornosion. For this use sufiicient of thecolloidal dispersion of MgCO for example, will be added to furnish from0.5 to 4.5 parts of magnesium per part of vanadium. The total amountneeded will of course depend on the vanadium content of the fuel oil,which may range anywhere from 5 to 1000 parts per million, for example.Magnesium carbonate dispersions may also be useful in fuel oils toreduce corrosion caused by sulfur, as by preventing or suppressingsulfur trioxide formation.

In either the fuel or lubricant compositions, other conventionaladditives may also be present including dyes, pour point depressants,antiwear agents, such as tricresyl phosphate or zinc dialkyldithiophosphate of 3 to 8 carbon atoms, antioxidants such asphenyl-alpha-naphthylamine, tert. octylphenol sulfide, bis-phenols suchas 4,4'-methylene bis (2,6-di tert. butylphenol), viscosity indeximprovers such as polymethylacrylates, polyisobutylene, alkylfumarate-vinyl acetate copolymers, and the like, as well as otherdispersants.

The dispersant-detergent additives of the invention may be used as thesole dispersant-detergent additives in lubricant composition or they maybe used to enhance the dispersancy-detergency of lubricants containingconvenional detergents, wherein the latter are used in concentrations inthe range of about 0.5 to 5 weight percent. Such detergents orcombination detergent-inhibitors in clude the alkaline earth metal saltsof alkylated phenols or of alkylated phenol sulfides, as for examplebarium-calcium nonyl phenol sulfide, calcium petroleum sulfonate bariumC alkyl benzene sulfonate, and the so-called overbased or highalkalinity alkaline earth metal sulfonates.

The dispersant-detergents of this invention may also be used inconjunction with ashless detergents or dispersants, as for example highmolecular weight polymeric multifunctional dispersants made with one ormore polar monomers, such as vinyl acetate, vinyl pyrrolidone,methacrylates, fumarates and maleates. These dispersants have molecularweights in the range of about 500 to 50,000. One example is a copolymerof 65 to weight percent of mixed C9-C12 fumarates, 10 to 20 weightpercent of vinyl acetate, and 5 to 15 Weight percent of N- vinylpyrrolidone. Another example is the copolymer derived by reaction ofmixed tallow fumarates and C oxo fumarates, averaging about 420molecular weight, with vinyl acetate in a 3 to 1 acetate-fumarate ratio,and 3 weight of maleic anhydride, followed by subsequent removal ofexcess vinyl acetate. By tallow fumarates is meant the esters of fumaricacid and the alcohols derived by hydrogenation of tallow. The latter areprincipally C and C alcohols with minor amounts of C C and C alcohols. Coxo alcohols are prepared by reaction of carbon monoxide and hydrogen onmixed C and C olefins followed by hydrogenation of the resultingaldehydes.

The following examples show the preparation of dispersants useful inthis invention.

PREPARATION OF DISPERSANT A A mixture of 180 pounds (0.180 pound mole)of polyisobutylene of about 800 molecular weight and 22.5 pounds (0.230pound mole) of maleic anhydride was heated for 24 hours at 450 F. undera nitrogen blanket to form polyisobutenyl succinic anhydride. Theproduct was found to have a saponification number of 86.6 mg. KOH/gm. ofreaction mixture. A light mineral lubricating oil having a viscosity of150 SUS at 100 F. was added as a diluent in suificient quantity toresult in a solution containing 75 weight percent of the polyisobutenylsuccinic anhydride. Then 30 ppm. of Dow Corning 60,000 cs. polymethylsilicone was added as an antifoamant. Next, 17.22 pounds (0.091 poundmole) of tetraethylene pentamine and 5.46 pounds (0091 pound mole) ofacetic acid were added. The reaction mixture was then heated at 300 F.for 10.5 hours while nitrogen was blown through it until no more Watercame off. The reaction product concentrate, after filtration, contained2.22 weight percent nitrogen based on the total product, i.e., theactual reaction product and oil diluent. This concentrate is referred tolater as Dispersant A.

PREPARATION OF DISPERSANT B A mixture of 240 pounds of polyisobutyleneof 1100 molecular weight (Staudinger), and 24 pounds of maleic anhydridewas heated at a temperature of about 485 F. for about 24 hours. Theheated mixture was then cooled to about 212 F., diluted with about 20gallons of heptane, and filtered through Hyfio filter aid using aSparkler filter. Then the heptane was evaporated by blowing nitrogenthrough the filtrate while heating at about 310 F. The heptane had beenused simply to reduce the viscosity of the reaction product to permiteasier filtering. The recovered alkenyl succinic anhydride reactionproduct was a viscous material of amber color, and had a saponificationnumber of 63.6 gm. KOH/ gm. of reaction product.

A mixture of 200 grams of the product alkenyl succinic anhydride thusprepared, 19.2 grams of tetraethylene glycol and 50 grams of toluene asa water-entraining agent was heated to reflux at 280 F. for 3 hours in areaction flask equipped with a Dean-Stark trap. Then 24.2 grams oftetraethylenepentamine was added to the reaction flask and reflux wascontinued at 280 F. for about two more hours until two ml. of water hadcollected in the Dean- Stark trap. The composition was then stripped ofthe toluene by nitrogen blowing on a steam bath, which took about 12hours. The residue was then cooled, and for convenience in handling, anoil solution was made up by dissolving 75 weight percent of the productin 25 weight percent of a light mineral lubricating oil. The resultingdispersant concentrate is hereafter referred to as Dispersant B.

PREPARATION OF DISPERSANT C Mixed dialkyldithiophosphoric acids wereprepared by reacting a mixture of 35 weight percent of primary amylalcohols and 65 weight percent of isobutyl alcohol with phosphorouspentasulfide using a mole ratio of alcohol to P 8 of 4 to 1. Thereaction was conducted at about 170 F. for a period of about 4 hoursuntil a specific gravity of about 1.05 was attained, measured at 78 F.The reaction product was then stripped of hydrogen sulfide with the aidof a stream of nitrogen, the product being cooled to about 90 to 100 F.,and the product was then filtered.

A mixture of 1200 parts by weight of Dispersant A (product concentrate)133 parts by weight of a phosphosulfurized hydrocarbon concentrate, and256 parts by weight of the dialkyldithiophosphoric acids prepared asjust described, was heated at 212 F. for 1 hour, with a stream ofnitrogen bubbling beneath the surface of the mixture. The product was avery viscous, oil-soluble material. It was diluted with 1589 parts byweight of solvent neutral mineral oil (150 SSU viscosity at F.), givinga 50 weight percent additive concentrate, hereinafter referred to asDispersant C. The phosphosulfurized hydrocarbon concentrate employedconsisted of 30 weight percent of light mineral oil and 70 weightpercent of the product obtained by reacting 100 parts by weight ofpolyisobutylene of 940 average molecular weight with 15 parts by weightof P 8 at 425 to 450 F. for 8 hours. The phosphosulfurizedpolyisobutylene analyzed about 3.5 weight percent of phosphorous andabout 6.6 weight percent of sulfur.

PREPARATION OF DISPERSANT D A -pound portion of polyisobutylene of 780molecular weight was heated to 250 F., then a stream of chlorine waspassed through the heated polyisobutylene at the 250 F. temperature at arate of 2.5 pounds of chlorine per hour for a total of 4 hours, to totalchlorine treat thus being 10 pounds. A sample of the chlorinated productanalyzed 4.3% chlorine and the product had an API gravity of 23.3. Tothe chlorinated polyisobutylene there was added 10.5 pounds of acrylicacid. Over a period of two hours the temperature was raised from 250 F.to 425 F. and the pressure was increased to 20 p.s.i.g. Heating wascontinued for 5 hours at 425 F. and the reaction vessel was vented tomaintain the pressure of 20 p.s.i.g. The pressure was then released andthe mixture was purged with nitrogen for 2 hours to remove unreactedacrylic acid. The polyisobutenyl propionic acid thereby obtained at theend of the reaction weighed 109.3 pounds and had a total neutralizationnumber (ASTM D-664) of 46.2 milligrams of KOH per gram. The clorinecontent was found to be 0.3 weight percent.

70-pound portion of the polyisobutenyl propionic acid obtained as justdescribed was mixed with 31.5 pounds of a solvent neutral minerallubricating oil SSU at 100 F.) and the resulting mixture was reactedwith 3.38 pounds of tetraethylenepentamine at 300 F. for 9 hours, themixture being maintained at reduced pressure (28 inches of vacuum) andpurged with a stream of nitrogen during the 9-hour reaction period toremove water as it was formed. The reaction mixture was then filteredthrough diatomaceous earth. The product analyzed 1.2 weight percentnitrogen and was in the form of a. concentrate containing about 70weight percent of reaction product and 30 weight percent of diluentmineral oil. Yield of product was 98.5 pounds.

PREPARATION OF DISPERSANT E Polyisobutenyl succinic anhydride of about1000 molecular weight prepared from polyisobutylene and maleic anhydrideis reacted with tetraethylene pentamine in the proportion of 3 moles ofthe anhydride to 1 mole of the pentamine, the two reactants being mixedtogether at about F. and then heated to 275 F., the latter temperaturebeing maintained for a period of about 6 hours while bubbling a streamof nitrogen beneath the liquid surface of the mixture. At the end of the6 hours, suflicient solvent neutral mineral oil (150 SUS at 100 F.) isadded to give a 75 weight percent concentrate of reaction product.

When preparing metal salt dispersions in accordance with the invention,numerous variations in the processing are possible. The followingprocesses were found particularly effective using an alkali metal oralkaline earth metal base, CO as the acidic gas, a succinic acidderivative as the dispersant, and alkyl phenol as the promoter.

13 Example 1 A mixture of 1000 grams of the additive concentrateDispersant A (75% active ingredient), 502 grams of nonylphenol, and 3825grams of a solvent refined mineral lubricating oil having a viscosity of150 SUS at 100 F. was prepared by simple mixing at ambient temperature.After the mixture was heated to 265 to 275 F., 3600 grams of bariumhydroxide pentahydrate was added over a period of 90 minutes while themixture was subjected to high speed stirring in an Eppenbach Homo-Mixersupplied by Gifford Wood Co., Hudson, NY. During the addition of thebarium hydroxide, 12.03 cubic feet of carbon dioxide was sparged into tomixture. This amount of carbon dioxide represents 110% of the equivalentamount of barium. Then the mixture was heated to 300 F. and kept at thistemperature for 30 minutes after which it was filtered with filter aid(Dicalite) yielding a reddish brown viscous liquid. The yield ofadditive amounted to 95% of theoretical. The calculated productcomposition is shown in Table III.

TABLE III The detergent-dispersant prepared in Example 1 can be comparedwith a representative commercial detergent inhibitor concentratecomprising a barium carbonate disperson prepared in the presence of analkyl phenol and a phosphosulfurized hydrocarbon, i.e., by reacting amixture of phosphosulfurizedpolyisobutylene and nonylphenol with Ba(OH)-5H O and carbon dioxide. The approximate analysis of the concentrate is27 weight percent of phosphosulfurized polyisobutylene, 11.7 weightpercent nonyl phenol, 13.1 weight percent barium carbonate and 48.2weight percent mineral oil. The concentration of organic constituents(other than diluent oil) in the concentrate of Example 1 is less thanhalf that of the commercial material and yet the barium carbonateconcentration in the Example 1 concentrate is about 2.5 times that ofthe commercial material.

Example 2 Example 1 was repeated, using the same procedure and the sameamount of Dispersant A concentrate (1000 grams) but employing less alkylphenol (462 grams), less barium hydroxide pentahydrate (2415 grams), andproportionately more mineral oil diluent, i.e., 4320 grams instead of3825 grams. Proportionately less CO was also used, and the time foraddition of barium hydroxide addition and CO treating was reduced to 60minutes. The product had a barium carbonate content of about 23 weightpercent and a diluent oil content of about 60 weight percent.

Example 3 A microemulsion technique was employed to prepare a calciumcarbonate dispersion using the following procedure. By the use of simplemixing at room temperature, 400 grams of the concentrate (Dispersant A)(300 grams of active material), 30 grams of tall oil fatty acids, 15grams of isopropanolamine, and 15 grams of diethylenetriamine weredissolved in 500 grams of a solvent refined neutral mineral oil having150 seconds Saybolt viscosity at 100 F. To this mixture, 15 grams ofwater was added with stirring to form a clear microemulsion. Themicroemulsion was heated to 160 to 170 F. and then 400 grams of calciumhydroxide was added with stirring, using a conventional paddle stirrer.The mixture was then heated to 210 to 215 F. and over a period of 2hours, 60 grams carbon dioxide was bubbled through the mixture while thetemperature was held at 210 to 215 F. Then nitrogen was sparged into themixture, which was heated to a tem- 14 perature of 300 to 320 F. andkept. at that temperature for 30 minutes under continuous nitrogensparging. Then the product was filtered with the aid of Dicalite filteraid giving a reddish-brown viscous liquid. The final product contained7.5 weight percent calcium as calculated from sulfated ashdetermination.

In the above preparation the amount of calcium hydroxide used was about130% in excess of the amount that is theoretically required. to give anadditive concentrate containing 7.5 weight percent calcium. In a secondpreparation using the same reactants in the same proportions butemploying only 50% excess lime calculated on the same basis the additiveconcentrate that was: obtained was found on analysis to contain 4.0weight percent calcium.

Other examples include the following:

Example 4 The procedure of Example 2 is repeated, substituting 1000grams of Dispersant B concentrate for the 1000 grams of Dispersant Aconcentrate and an equivalent amount of S0 for the CO Example 5 Theprocedure of Example 1 is repeated employing in place of Dispersant A,1400 grams of Dispersant C concentrate and proportionately less mineraloil diluent, i.e., about 3400 grams.

Example 6 The procedure of Example 2 is repeated substituting 900 gramsof Dispersant E concentrate for Dispersant A.

Example 7 Example 3 is repeated, using, in place of Dispersant A, acommercially available concentrate consisting of 25 weight percent ofmineral lubricating oil and 75 weight percent of a succinimide havingthe formula wherein R is a polyisobutenyl group of about 800 molecularweight.

Similar techniques can be used with the other dispersants, acidic gases,metal bases, promoters, etc., previously mentioned.

Example 8 To a three gallon bafiled vessel equipped with an efficientmixer there are charged: 455 grams of Dispersant D and 3850 grams ofneutral mineral oil (150 SSU at F.). The contents are heated withstirring to 260 to 280 F., and 354 grams of crude nonyl phenol (averagemolecular weight 251) is charged to the mix. Maintaining the temperatureat 260 to 280 F., 1515 grams of sodium hydroxide as a 50% aqueoussolution and 857 grams of CO are charged simultaneously at a constantrate over a period of minutes. Following this step the temperature ofthe neutralization mix is raised to 300 F., and the mix is soaked for 15minutes. The raw neutralization mix at 300 to 310 F. plus 50 grams offilter aid is then filtered.

The following test results illustrate the utility and advantages of thisinvention.

Example 9 Using as the base oil a mineral lubricating oil having aviscosity of 325 SUS at 100 F. and. a viscosity index of about 100, thefollowing compositions were prepared:

Composition 1.-3.5 Weight percent of a commercial detergent inhibitor,0.9 weight percent of a zinc dialkyldithiophosphate antiwear additive,95.6 weight percent of the base oil.

Composition 2.--2.0 weight percent of the concentrate product of Example2, 1.07 weight percent of Dispersant A concentrate, 0.9 weight percentof a zinc dialkyldithiophosphate antiwear additive, 96.03 weight percentof th base oil.

Composition 3.--1.33 weight percent of the concentrate product ofExample 3, 0.89 Weight percent of Dispersant A, 0.9 weight percent of azinc dialkyldithiophosphate antiwear additive, 96.88 weight percent ofthe base oil.

The commercial detergent inhibitor mentioned above was a mineral oilsolution containing an additive prepared by reacting a mixture ofphosphosulfurized polyisobutylene and nonyl phenol with barium hydroxidepentahydrate and blowing the reaction mixture with car bon dioxide. Theapproximate analysis of the concentrate was 27 weight percent ofphosphosulfurized polyisobutylene, 11.7 weight percent nonyl phenol,10.6 weight percent barium oxide, 2.5 weight percent carbon dioxide, and48.2 weight percent of mineral oil.

The zinc dialkyldithiophosphate antiwear additive was an oil solutionconsisting of about 25 Weight percent of mineral lubricating oil andabout 75 weight percent of zinc dialkyldithiophosphate prepared bytreating a mixture of isobutanol and mixed amyl alcohols with P 8followed by neutralizing with zinc oxide.

Each of the compositions 1 to 3 described above was tested for sludgedispersing ability in the ER 4-90 Ford sludging test. Prior experiencehas shown that this sludging test gives sludge deposits similar to thoseobtained in stop-and-go driving, such as would be experienced in taxicaboperation. Briefly described, in this test a Ford 6- cylinder engine isrun on a dynamometer stand through varying cycles consisting of a firstcycle operating at 500 r.p.m. for 1% hours, a second cycle operating at2000 rpm. for 2 hours, and a third cycle also operating at 2000 -r.p.m.for 2 hours but using slightly higher oil sump and water jackettemperatures. The three cycles are repeated over and over again insequence until the desired total test time has elapsed. Make-up oil isadded as required so that the crankcase oil level is maintained at alltimes between about 3 /2 and 4 quarts. After a selected test time haselapsed, the engine is inspected by disassembling it sufficiently topermit visual examination of the rocker arm cover, the rocker armassembly, the cylinder head, the push rod chamber, the push rod chambercover, the crankshaft, the oil pan, and the oil screen. The oil screenis rated as percent covered with sludge and the other parts are visuallyrated for sludge deposition using a merit system in which a numericalrating of 10 represents a perfectly clean part and 0 a part covered withthe maximum amount of sludge possible. These individual merit ratingsare then averaged to give an overall engine merit rating.

The results of the ER 490 test are summarized in Table IV. The durationof the test was 286 hours.

TABLE IV.ER 490 ENGINE TEST RESULTS Percent coverage It will be seenthat each of the compositions containing an additive of the presentinvention gave better performance than the composition containing thecommercial detergent additive.

In summary, the present invention concerns the preparation of acolloidal dispersion of a metal salt, which dispersion can be referredto as an over-based detergentdispersant, wherein said colloidaldispersion is prepared by forming the metal salt by reaction of a metalbase with a normally gaseous acidic reactant in the presence of anitrogen-containing ashless dispersant that is characterized as anitrogen-containing derivative prepared from a highmolecular-weightcarboxylic acid, i.e., a monocarboxylic or polycarboxylic acid having inthe range of about 40 to 250 carbon atoms, and from a nitrogen compoundhaving at least one reactive amino group or hydroxy group. All of thesedispersants have a common characterstics; that is, all of them have along chain, which is present in the carboxylic acid portion of theproduct, and all of them contain nitrogen either in the form of an aminogroup or a heterocyclic nitrogen atom. Typically, the nitrogencontainingportion of the dispersant is derived from an alkylene polyamine havingfrom 2 to 12 nitrogen atoms and 2 to 33 carbon atoms or from a hydroxyalkyl amine having 2 to 12 nitrogen atoms, 2 to 33 carbon atoms, and 1to 4 hydroxy groups, or from an N-hydroxy alkyl morpholinone having atotal carbon atom content within the range of about 6 to 30 carbonatoms, the hydroxy alkyl group having from 2 to 4 carbon atoms. Theproduct of reaction between the high molecular weight carboxylic acidand the nitrogen compound is usually either an amide, an imide, or anester, although it can be a simple amine salt.

The present invention is based on the discovery that the above-describednitrogen-containing dispersants, all of which are known to the art aslubricant additives, are outstandingly effective in their ability tomaintain a colloidal dispersion of the metal salt that is prepared insitu in the presence of the dispersant so that a metal containingdetergent-dispersant having an especially high ratio of metal todispersant can be prepared. The results that are given in the foregoingexamples are typical illustrations of the ability of thesenitrogen-containing dispersants to accomplish the objects of theinvention. The effectiveness of the nitrogen-containing dispersants toattain high ratios of metal to dispersant is demonstrated, for instance,by Example 1 of this specification wherein it was shown that it ispossible to prepare a colloidal dispersion having a concentration oforganic constituents less than half of a commercial material while atthe same time having a concentration of metal salt about 2 /2 times thatof the commercial material.

The dispersants employed in the present invention perform two functions;i.e., they maintain the colloidal dispersion and they also impartdispersency to the lubricating compositions to which the colloidaldispersion is added. At the same time, the colloidally dispersed metalsalt contributes detergency to the composition.

While the lubricant compositions herein described are primarily designedas automotive crankcase lubricants, the additives of the invention mayalso be employed in other hydrocarbon oil compositions including turbineoils, various industrial oils, gear oils, hydraulic fluids, transmissionfluids and the like.

It is to be understood that the examples presented herein are intendedto be merely illustrative of the invention and not as limiting it in anymanner; nor is the invention to be limited by any theory regarding itsoperability. The scope of the invention is to be determined by theappended claims.

What is claimed is:

1. A process for preparing an overbased detergentdispersant for an oilcomposition which comprises reacting at a temperature in the range offrom about 50 to about 400 F. a metal base with a normally gaseousacidic reactant, whereby a metal salt is formed, in the presence of adispersant comprising the product of reacting a high molecular weightcarboxylic acid, having in the range of about 40 to 250 carbon atoms,with an organic nitrogen-containing compound having at least onereactive amino group or hydroxy group, said dispersant being capable ofcolloidally suspending the said metal salt, said dispersant beingselected from the class consisting of the amides, imides, and esters ofsaid carboxylic acid, said organic nitrogen-containing amino compoundbeing selected from the class consisting of alkylene polyamines,hydroxyalkyl amines and N-hydroxy alkyl morpholinones, the proportion ofdispersant to metal base being in the range of from to 35 parts byweight of dispersant to from to parts by weight of said metal base.

2. Process as defined by claim 1 wherein said metal base is selectedfrom the class consisting of alkali metal oxides, alkaline earth metaloxides, alkali metal hydroxides and alkaline earth metal hydroxides, andsaid acidic gas is carbon dioxide.

3. Process as defined by claim 1 wherein said reaction is conducted in amineral oil solution of said dispersant.

4. Process as defined by claim 1 wherein said process is conducted inthe presence of a promoter capable of assisting in the transfer of metalsalts from a polar phase to an oil phase.

5. A mineral oil composition comprising a major proportion of a mineraloil selected from the class consisting of middle distillate fuels,residual fuels, and lubricating oils and from 0.001 to 10 weight percentof the product prepared by the process of claim 1.

6. The product prepared by the process of claim 1.

7. A mineral oil composition comprising a major proportion of a mineraloil selected from the class consisting of middle distillate fuels,residual fuels, and lubricating oils and sutficient of the additive ofclaim 6 to furnish in the composition from about 0.01 to 3 weightpercent of metal.

8. A detergent-dispersant additive concentrate comprising from 5 to 50weight percent of an oil-soluble dispersant and from 10 to 35 weightpercent of a metal salt, said concentrate having been prepared byreacting at a temperature in the range of about 50 to about 400 F. ametal base with a normally gaseous acidic reactant, thereby forming saidmetal salt in the presence of said dispersant, said dispersant beingselected from the class consisting of the amides, imides, and esters ofa high molecular weight carboxylic acid having in the range of about 40to 250 carbon atoms with an organic nitrogen compound having at leastone reactive amino group or hydroxy group and being selected from theclass consisting of alkylene polyamines, hydroxyalkyl amines andN-hydroxy alkyl morpholinones.

9. An overbased detergent-dispersant additive for an oil compositionwhich comprises a colloidal dispersion of a metal salt of a normallygaseous inorganic acid colloidally suspended with a dispersant selectedfrom the class consisting of the amides, imides, and esters of a highmolecular weight carboxylic acid having in the range of about 40 to 250carbon atoms and of an organic nitrogen-containing amino compoundselected from the class consisting of alkylene polyamines, hydroxyalkylamines and N-hydroxy alkyl morpholinones.

10. Additive as defined by claim 9 wherein the proportion of dispersantto metal salt is in the range of from 5 to 35 parts by weight ofdispersant to from 10 to 50 parts by weight of metal salt.

11. Additive as defined by claim 9 wherein said metal salt is acarbonate salt.

12. Additive as defined by claim 9 wherein said metal salt is selectedfrom the class consisting of the carbonates of alkali metals andalkaline earth metals.

13. Additive as defined by claim 9 wherein said dispersant is thereaction product of an alkenyl succinic anhydride and an alkylenepolyamine.

14. Additive as defined by claim 13 wherein said alkenyl succinicanhydride has an alkenyl group derived from a C to C monoolefin polymerhaving a molecular Weight in the range of from 500 to 3500.

15. Additive as defined by claim 9 wherein said dispersant is thereaction product of an alkenyl succinic anhydride, a polyamine and analiphatic carboxylic acid of from 1 to 30 carbon atoms.

16. Additive as defined by claim 9 wherein said dispersant is thereaction product of an alkenyl succinic anhydride with a polyamine and apolyhydric alcohol of from 2 to 36 carbon atoms.

17. Additive as defined by claim 9 wherein said dispersant is thereaction product of tetraethylene pentamine, acetic acid and an alkenylsuccinic anhydride wherein the alkenyl group is derived frompolyisobutylene of from about 700 to about 1700 molecular weight.

18 Additive as defined by claim 9 wherein said dispersant is thereaction product of tetraethylene pentamine, acetic acid andpolyisobutenyl succinic acid which has been further reacted with amixture of a phosphosulfurized polyisobutylene and mixed C to C dialkyldithiophosphoric acids.

19. Additive as defined by claim 9 wherein said dispersant is thereaction product of polyisobutenyl succinic anhydride, tetraethyleneglycol and tetraethylene pentamine.

20. Additive as defined by claim 9 wherein said dispersant is the amideof polyisobutenyl propionic acid and an alkylene polyamine.

References Cited UNITED STATES PATENTS 3,342,733 9/1967 Robbins et a1.3,163,603 12/1964 Le Suer 252-33.6 3,271,310 9/1966 Le Suer 252----37 XR3,311,558 3/1967 Prizer et al. 252-47.5 3,321,399 5/1967 Versteeg et a1.252-18 XR PATRICK P. GARVIN, Primary Examiner.

US. Cl. X.R.

